Drinking Water Distribution Systems Assessing and Reducing Risks (2006) / Chapter Skim
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8 Alternatives for Premise Plumbing
8 Alternatives for Premise Plumbing
Pages 316-340
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From page 316... ...
rule in which drinking water quality is purposefully measured within premise plumbing is the Lead and Copper Rule (LCR) for which samples are collected at the tap after the water has been allowed to remain stagnant.
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From page 317... ...
Temperature 030° C 0100° C (at the surface of heating elements) Control of Water Quality Utility treatments and No control over water coming into operation home, but home treatment devices and selection of plumbing materials can influence water quality Ownership Utility End user Maximum Cost over 30 $500$7,000 US As much as $25,000 per homeowner, Years per Consumer frequency determined by lifetime of plumbing Financial Responsibility Distributed burden over Individual consumer time and large cus tomer base Cross Connections Relatively rare Widely prevalent Frequency of Sample Regular sampling re- Often sampled only in reactive mode to Collection and quired by regulation consumer complaints Evaluation of WQ and industry best Degradation standards *
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From page 318... ...
The impact of water quality changes on the performance of materials within premises, and the effects of materials on water quality within premises, are often overlooked by water utilities. For instance, Brazos et al.
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From page 319... ...
The sampling of the main distribution system cannot capture effects of these variations on water quality in premise plumbing, particularly in relation to microbial type and concentrations. This is especially true for moderate thermophiles such as Legionella in water heaters.
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From page 320... ...
As discussed in Chapter 3, outbreaks in healthcare facilities of Legionnaire's disease have been attributed to Legionella pneumophila in hot water tanks and showerheads. There is some evidence that nontuberculous mycobacteria may colonize biofilms, and the species found in treated drinking water have been linked to infections in immunocompromised individuals.
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From page 321... ...
This can greatly complicate the extent to which service lines are inspected, replaced, and repaired in a timely manner when leaking. In most cases a drinking water utility, and thus most regulatory bodies, only takes responsibility for the quality of water delivered to the corporation stop, curb stop, or water meter.
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From page 322... ...
But ultimately individual homeowners and building supervisors bear final responsibility for protecting themselves from excessive lead or copper exposure and other degradation to water quality occurring beyond the property line. Economic Considerations.
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From page 323... ...
No drinking water maximum contaminant levels (MCLs) protect consumers against water quality degradation resulting from premise plumbing.
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From page 324... ...
Nor have studies correlated Legionella occurrence and concentrations in drinking water with actual outbreaks of legionellosis. Targeted research to improve understanding of water quality degradation within premise plumbing is recommended and must overcome several challenges.
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From page 325... ...
The implicated beverage had been prepared on-site using a powder mix and water drawn from a spigot near the fire hall heating system that used a mixture of water and antifreeze and was cross-connected to the potable water supply. There was a valve on the cross-connection but no information on whether the valve had been closed before collecting water to prepare the beverage.
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From page 326... ...
WHY HOME TREATMENT DEVICES ARE NOT ALWAYS THE ANSWER Home treatment devices have become increasingly popular as a means to further treat drinking water supplied by public water systems, and they are considered to be a potential technical solution to some problems associated with premise plumbing. There are a myriad of available devices designed to remove organic and inorganic chemicals, radionuclides, and microbiological agents from tap water.
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From page 327... ...
Each water sample is field tested for chlorine residual, turbidity, pH, iron, and copper at the site. If the water meets the national drinking water quality standards, the team issues and attaches a water quality certification on the faucet.
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From page 328... ...
. Granular activated carbon in point-of-use treatment devices can accumulate nutrients and neutralize disinfectant residuals, thereby providing an ideal environment for microbial growth (Tobin et al., 1981; Geldreich et al., 1985; Reasoner et al., 1987; LeChevallier and McFeters, 1988)
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From page 329... ...
. To ensure that water storage is hot enough to prevent microbial regrowth but that delivered water temperatures are not high enough to cause scalding, one solution is to install a plumbing device that physically limits the percentage of hot water flowing to the tap based on target delivery temperatures.
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From page 330... ...
In the Netherlands, the owners of collective water systems including hotels, camp sites, and sports facilities have been required to complete a risk analysis for microbial regrowth. The focus was mostly on Legionella, but a new Drinking Water Directive 98/83/EC also will eventually consider other microbial parameters at the tap (Regal et al., 2003)
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From page 331... ...
Checklists are provided for tank cleaning and water quality analysis and inspection. The program was started in July 2002; 32 months later, 2,807 certificates had been issued for residential buildings, hotels, and restaurants.
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From page 332... ...
A multifaceted and long-term approach to providing safe drinking water from the treatment plant to the water meter is already used by the drinking water industry -- one that involves compliance with the Safe Drinking Water Act, use TABLE 8-3 World-wide Perspectives on Responsible Party to Prevent Degradation of Water Within Premise Plumbing. Country Approach U.S.A.
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From page 333... ...
Concepts such as the value of water, the need to conserve water (which has already taken place in some areas of the United States) , and the need for good materials in guaranteeing good water quality are basic to bringing about solutions to problems the drinking water industry is faced with.
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From page 334... ...
Changes in the plumbing code such as those considered in Canada and Australia that involve mandated mixing valves would seem logical as a compromise that would prevent both scalding and microbial regrowth in premise plumbing water systems. On-demand water heating systems may have benefits worthy of consideration versus traditional large hot water storage tanks in the United States.
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From page 335... ...
Furthermore, the role of nutrients in distributed water in controlling regrowth should be assessed for premises because their longer holding times, chronic lower disinfection residuals, warmer temperatures, and most importantly their colonization by opportunistic pathogens such as Legionella and Mycobacterium avium make the biological stability of the water even more important than in the main distribution system. Specialized sampling is needed to quantify regrowth of opportunistic pathogens such as Legionella and Mycobacteria as a function of consumer water use patterns, plumbing system layout, and water heater operation.
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From page 336... ...
2002. Appendix K of drinking water and sewer systems in corrosion costs and preventative strategies in the United States.
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From page 337... ...
2005. A ran domized controlled trial of in-home drinking water intervention to reduce gastroin testinal illness.
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2002b. Guidance for Implementing a Point-of-Use or Point-of-Entry Treatment Strategy for Compliance with the Safe Drinking Water Act Revised Final Draft.
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From page 339... ...
2004. Investigation of opportunistic pathogens in municipal drinking water under different supply and treatment regimes.
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From page 340... ...
2005. Myco bacteria in drinking water distribution systems: Ecology and significance for human health.
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